Cells have been used or proposed for use in treating a variety of diseases. A variety of techniques have been developed for delivering cells to an appropriate area of a patient so that the cells can exert a therapeutic effect. However, in some circumstances, the cells are not readily retained in the appropriate area. For example, implantation of exogenous cells into intervertebral discs is an experimental therapeutic approach for treating chronic back pain associated with disc degeneration, but high pressures within the disc space may force the exogenous cells to exit the intervertebral space, e.g., along a track left by a cannula used to introduce the cells.
One way to address the cell retention issue is to seed the cells on a mesh or sponge material prior to introducing the cells into the patient, which can also provide a scaffold for cell growth. Depending on the size of the material, delivery of the cells may require invasive surgical methods. If the cell-seeded material is sufficiently small, a minimally invasive surgical procedure may be used. However, implantation of pre-seeded material requires multiple steps; namely, seeding and delivery. Each step can introduce variability into the procedure and can raise likelihood that the material will become contaminated or that the cell properties will change prior to implantation.